The invention relates to a method and a device for processing printed products made of multiple paper sheets as well as a perforating knife.
Printed products which have only a longitudinal fold, but not a cross fold, are generally known. After printing a paper web in a web-fed printing press, these printed products are guided via a former, provided there with the longitudinal fold, and then severed from the folded ribbon formed in the process by a cutting knife cylinder, i.e., detached. Since these printed products and the leading cut edge formed in the process are open, it is possible for the individual pages to fan out. Especially during the further transport of the printed products, this may result in tears, dog-earing, i.e., corners of pages being turned down, or other damage.
Starting herefrom, the object of the invention is creating a method and a device which prevents damage to the printed products from the fanning out of individual pages.
Because of the inventive positive connection of the paper sheets of a printed product in the region of an open, i.e., unfolded, edge, the printed product may be moved forward with this product edge without the individual pages fanning out. In particular, when further transporting the printed products to additional processing stations, tears, dog-earing or other damage is advantageously prevented.
The invention is especially advantageous in the case of folding units which apply only a longitudinal fold to the printed products and where the printed products are moved further with their open, i.e., unfolded, side pointing forward.
The invention is explained in greater detail in the following on the basis of the associated schematic drawings.